| [GMCnet] ELECTRIC ACTUATOR FOR PARKING BRAKES [message #104634] |
Sat, 30 October 2010 17:12  |
Charles Aulgur
Messages: 78
Registered: March 2006
Karma: 0
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Member |
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Jim has found an American made electric scissors jack that he is
having shipped to me that may be better then the Harbor Freight unit
made in China. He wants me to see if I can design a 12 vdc actuator
to actuate the Caddy calipers when changing to the reaction arm rear
brake system. He didn't like the first one I did because it did not
have the capability of being released if the electric actuator failed
in the applied position. One problem is how to determine when you
have the proper loads applied to the Caddy calipers. Do any of you
electrical experts know if someone makes a simple adjustable current
limit switch that could shut of the power to a electric motor when a
certain amperage is reached? It needs to shut off the power directly
or actuate a solenoid relay to shut off the power and not re-set
until power is again applied to the electric motor. I have searched
on the net but all I found were expensive electronic boxes controlled
by a computer.
Chuck Aulgur
La Mesa, CA
76 Royale with excellent brakes
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| Re: [GMCnet] ELECTRIC ACTUATOR FOR PARKING BRAKES [message #104690 is a reply to message #104687] |
Sun, 31 October 2010 12:11  |
Marsh Wilkes
Messages: 155
Registered: January 2004
Karma: -3
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Senior Member |
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Charles,
Here is a link to one manufacturer and their offering in the range you would
need. The units can be paralleled for increased amprage
http://www.tycoelectronics.com/catalog/bin/TE.Connect?C=22878&M=FEAT&P=151641,146370&U=&I=13&G=G
Hopefully the link will come through complete
Marsh (on the way to work) Wilkes
----- Original Message -----
From: "Marsh Wilkes" <gmc455@comcast.net>
To: <gmclist@temp.gmcnet.org>
Sent: Sunday, October 31, 2010 1:01 PM
Subject: Re: [GMCnet] ELECTRIC ACTUATOR FOR PARKING BRAKES
>
>
> Hi Charles,
>
> I actually have a manufacturers catalog of the devices I was referring to,
> naturally I cant find it right now. However here is a link to a wickipedia
> article on the class of device I am referring to. I looked at using these
> devices as an automatic stop for a motorized truck tool box lid opener
> several years ago. I will try to find some more info, but you should be
> able
> to take it from here with the information in the article. Good luck with
> the
> project.
>
> http://en.wikipedia.org/wiki/Resettable_fuse
>
>
>
> Marsh Wilkes
> Perry Florida
>
>
>
>
>
>
>
> ----- Original Message -----
> From: "Charles Aulgur" <cwasdc@sbcglobal.net>
> To: "GMCnet" <gmclist@temp.gmcnet.org>
> Sent: Saturday, October 30, 2010 6:12 PM
> Subject: [GMCnet] ELECTRIC ACTUATOR FOR PARKING BRAKES
>
>
>> Jim has found an American made electric scissors jack that he is
>> having shipped to me that may be better then the Harbor Freight unit
>> made in China. He wants me to see if I can design a 12 vdc actuator
>> to actuate the Caddy calipers when changing to the reaction arm rear
>> brake system. He didn't like the first one I did because it did not
>> have the capability of being released if the electric actuator failed
>> in the applied position. One problem is how to determine when you
>> have the proper loads applied to the Caddy calipers. Do any of you
>> electrical experts know if someone makes a simple adjustable current
>> limit switch that could shut of the power to a electric motor when a
>> certain amperage is reached? It needs to shut off the power directly
>> or actuate a solenoid relay to shut off the power and not re-set
>> until power is again applied to the electric motor. I have searched
>> on the net but all I found were expensive electronic boxes controlled
>> by a computer.
>>
>> Chuck Aulgur
>> La Mesa, CA
>> 76 Royale with excellent brakes
>> _______________________________________________
>> GMCnet mailing list
>> List Information and Subscription Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] ELECTRIC ACTUATOR FOR PARKING BRAKES [message #104761 is a reply to message #104634] |
Mon, 01 November 2010 11:25 |
GMC_LES
Messages: 569
Registered: October 2009
Location: Montreal
Karma: 0
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Senior Member |
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Am I correct in assuming that the driving force behind an improved Park Brake
system is the concern about being able to apply enough force to a set of Caddy
rear calipers to hold a GMC secure?
For me, this raises a few additional questions/comments:
1) Is the caddy caliper park brake mechanism & lever robust enough to handle the
increased forces needed for the GMC? Branscombe appears to be concerned about
this as mentioned in his recent caliper testing report.
2) Are 2 or 4 Cad calipers needed at the rear of the GMC for an efficient park
brake?
3) Would using 4 Cad calipers require more pulling force and possibly more cable
travel as compared to using 2 calipers.?
4) Has anyone considered using a spring as a cable tension control device?
A spring could be used to control the min & max pull forces applied to the rear
calipers, which would protect the caliper mechanisms from excessive pulling
forces as well as provide compensation for slight cable stretch, reducing the
need for frequent adjustment.
Another benefit of using such a spring would be that the precise length of pull
applied to the cable would be of less importance as the spring would act as a
buffer. This might help in the quest for a low cost electrical actuator that can
produce controllable & repeatable cable pull specs.
I'm just babbling, so if none of this makes sense or is of any use, just ignore
me!!!
Thanks,
Les Burt
________________________________
From: Charles Aulgur <cwasdc@sbcglobal.net>
To: GMCnet <gmclist@temp.gmcnet.org>
Sent: Sat, October 30, 2010 6:12:52 PM
Subject: [GMCnet] ELECTRIC ACTUATOR FOR PARKING BRAKES
Jim has found an American made electric scissors jack that he is
having shipped to me that may be better then the Harbor Freight unit
made in China. He wants me to see if I can design a 12 vdc actuator
to actuate the Caddy calipers when changing to the reaction arm rear
brake system. He didn't like the first one I did because it did not
have the capability of being released if the electric actuator failed
in the applied position. One problem is how to determine when you
have the proper loads applied to the Caddy calipers. Do any of you
electrical experts know if someone makes a simple adjustable current
limit switch that could shut of the power to a electric motor when a
certain amperage is reached? It needs to shut off the power directly
or actuate a solenoid relay to shut off the power and not re-set
until power is again applied to the electric motor. I have searched
on the net but all I found were expensive electronic boxes controlled
by a computer.
Chuck Aulgur
La Mesa, CA
76 Royale with excellent brakes
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Les Burt
Montreal
1975 Eleganza 26ft
A work in Progress
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| Re: [GMCnet] ELECTRIC ACTUATOR FOR PARKING BRAKES [message #104895 is a reply to message #104761] |
Tue, 02 November 2010 22:02 |
Carleton Douglas[1]
Messages: 174
Registered: March 2006
Karma: 0
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Senior Member |
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A spring could be used to set and hold the caliper in the park pushion
and air to reset the spring to the ready just like air brakes work.
On Mon, Nov 1, 2010 at 9:25 AM, Les Burt <burtco99@yahoo.com> wrote:
> Am I correct in assuming that the driving force behind an improved Park Brake
> system is the concern about being able to apply enough force to a set of Caddy
> rear calipers to hold a GMC secure?
>
> For me, this raises a few additional questions/comments:
>
> 1) Is the caddy caliper park brake mechanism & lever robust enough to handle the
> increased forces needed for the GMC? Branscombe appears to be concerned about
> this as mentioned in his recent caliper testing report.
>
> 2) Are 2 or 4 Cad calipers needed at the rear of the GMC for an efficient park
> brake?
>
>
> 3) Would using 4 Cad calipers require more pulling force and possibly more cable
> travel as compared to using 2 calipers.?
>
> 4) Has anyone considered using a spring as a cable tension control device?
>
> A spring could be used to control the min & max pull forces applied to the rear
> calipers, which would protect the caliper mechanisms from excessive pulling
> forces as well as provide compensation for slight cable stretch, reducing the
> need for frequent adjustment.
> Another benefit of using such a spring would be that the precise length of pull
> applied to the cable would be of less importance as the spring would act as a
> buffer. This might help in the quest for a low cost electrical actuator that can
> produce controllable & repeatable cable pull specs.
>
> I'm just babbling, so if none of this makes sense or is of any use, just ignore
> me!!!
>
>
> Thanks,
> Les Burt
>
>
>
>
> ________________________________
> From: Charles Aulgur <cwasdc@sbcglobal.net>
> To: GMCnet <gmclist@temp.gmcnet.org>
> Sent: Sat, October 30, 2010 6:12:52 PM
> Subject: [GMCnet] ELECTRIC ACTUATOR FOR PARKING BRAKES
>
> Jim has found an American made electric scissors jack that he is
> having shipped to me that may be better then the Harbor Freight unit
> made in China. He wants me to see if I can design a 12 vdc actuator
> to actuate the Caddy calipers when changing to the reaction arm rear
> brake system. He didn't like the first one I did because it did not
> have the capability of being released if the electric actuator failed
> in the applied position. One problem is how to determine when you
> have the proper loads applied to the Caddy calipers. Do any of you
> electrical experts know if someone makes a simple adjustable current
> limit switch that could shut of the power to a electric motor when a
> certain amperage is reached? It needs to shut off the power directly
> or actuate a solenoid relay to shut off the power and not re-set
> until power is again applied to the electric motor. I have searched
> on the net but all I found were expensive electronic boxes controlled
> by a computer.
>
> Chuck Aulgur
> La Mesa, CA
> 76 Royale with excellent brakes
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Carleton Douglas
73 custom, by myself
Prescott, AZ
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